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The Difference Between Food Allergy and Food Intolerance

So what really IS the difference between a food allergy and food intolerance? First off, food allergies are not uncommon in the pediatric population. About 8% of young children are affected by IgE-mediated reactions. Childhood food allergy has increased by 18% in the last decade in the United States with almost 6 million American children having this problem.

But up to a third of parents report their child has a food-related problem. Most of those never prove to be food allergies. Health professionals need to understand how to evaluate these claims by parents and distinguish allergy from other causes.

Food allergy is completely different from food intolerance. A food allergy involves an immune system response, food intolerance does not.  If you have a food allergy you cannot properly digest a substance in certain foods, often because you have an enzyme deficiency. Food allergy has nothing to do with enzyme deficiency.

Features associated with food allergy or intolerance

Below are some features associated with either a food allergy or intolerance:

Onset of symptoms

  • Food allergy symptoms appear soon after eating the culprit food.
  • Food intolerance symptoms appear later.

Amount of problem food eaten

  • A person with a food allergy cannot tolerate even small amounts of the culprit food, as is the case with peanuts.
  • With food intolerance, a very small amount of the food can be consumed with no adverse reaction.

An immune response versus an enzyme deficiency

  • In a food allergy, a protein causes an allergic reaction (an immune response). An “allergen” is a protein that causes a food allergy.
    • This is called an Immediate hypersensitivity response or IgE reaction. Reaction generally appears within 12 minutes of an antigen challenge. These reactions are mediated by T cells and monocytes/macrophages rather than by antibodies. They are also termed type IV hypersensitivity reactions.
    • Allergens are not harmful in themselves, i.e., most people can be exposed to them without any adverse effects. They are called allergens because they affect some people by triggering a response in their immune system.
  • In food intolerance, the person usually has an enzyme deficiency, meaning that a substance in the food is not digested properly.
    • Food intolerances create a delayed hypersensitivity reaction (DTH). If food intolerances go on long enough they may be able to pass through the gut barrier where they can begin to produce an immune response called a delayed-hypersenstivity response. DTH most commonly is the major mechanism of defense against various intracellular pathogens, including mycobacteria, fungi, and certain parasites, and it occurs in transplant rejection and tumor immunity. DTH reaction can last 7-10 days resulting in low grade inflammation. Undesirable consequences of DTH is the result of your body trying to clear the antigens (the problem food).
    • Most common symptoms of DTH are rashes, dermatitis, and autoimmune disease (crohns, Lupus, or Celiacs), headaches, and depression

Food allergies can be life-threatening

  • In some cases of food allergy, there can be a severe and life-threatening allergic reaction (anaphylaxis) to certain foods.
  • Food intolerance adverse reactions can be severe and extremely unpleasant, but are rarely life-threatening, but do contribute to chronic disease, like autoimmune diseases.

How do Food Intolerances happen?

Food intolerance is relatively new in its research so there are still many questions. They may be caused by certain chemicals in and on foods, food poisoning (toxins), the natural occurrence of histamine in some foods, salicylates which are present in many foods, and food additives.

Previous research has drawn parallels between the rise in allergies and increased antibiotic and antimicrobial use. According to British researchers, exposure to antibiotics early in life may increase your child’s risk of developing eczema by 40 percent.

Other scientists have clearly shown how genetically engineered foods and the use of the agricultural herbicide glyphosate destroys gut bacteria and promotes allergies. One recent study adds further credence to the disturbed microbiome hypothesis.

Dr. Cynthia Preston, ND

Written by Dr. Cynthia Preston

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The information provided in this site is intended for general informational purposes only. It is not a substitute for medical advice and is not intended to provide complete medical information. KidsMisdiagnosed, Inc does not offer personalized medical diagnosis of patient-specific treatment advice. All medical information presented should be discussed with your healthcare professional. Remember, the failure to seek timely medical advice can have serious ramifications. KidsMisdiagnosed, Inc urges you to discuss any current health related problems you or your child are experiencing with a healthcare professional immediately.